title: Pioglitazone improves glucose metabolism and modulates skeletal muscle TIMP-3-TACE dyad in type 2 diabetes mellitus: a randomised, double-blind, placebo-controlled, mechanistic study.
abstract: OBJECTIVE
  Pioglitazone (PIO) is a peroxisome proliferator-activated receptor (PPAR)γ agonist insulin-sensitiser with anti-inflammatory and anti-atherosclerotic effects. Our objective was to evaluate the effect of low-dose PIO (15 mg/day) on glucose metabolism and inflammatory state in obese individuals with type 2 diabetes.
  
  
  METHODS
  A randomised, double-blind, placebo-controlled, mechanistic trial was conducted on 29 patients with type 2 diabetes treated with metformin and/or sulfonylurea. They were randomised to receive PIO or placebo (PLC) for 6 months, in a 1:1 ratio. Participants were allocated to interventions by central office. All study participants, investigators and personnel performing measurements were blinded to group assignment. At baseline and after 6 months patients underwent: (1) OGTT; (2) muscle biopsy to evaluate expression of TNF-α, tissue inhibitor of metalloproteases 3 (TIMP-3) levels, TNF-α converting enzyme (TACE) expression and enzymatic activity; (3) euglycaemic-hyperinsulinaemic clamp; (4) measurement of plasma high-sensitivity C-reactive protein (hsCRP), plasminogen activator inhibitor type-1 (PAI-1), TNF-α, IL-6, monocyte chemotactic protein-1 (MCP-1), adiponectin and fractalkine (FRK). The interventions were PIO 15 mg/day vs placebo and the main outcomes measured were absolute changes in whole-body insulin sensitivity, insulin secretion and inflammatory state.
  
  
  RESULTS
  Fifteen participants were randomized to receive PIO and 14 participants were randomized to receive PLC. Eleven participants completed the study in the PIO group and nine participants completed the study in the PLC group and were analysed. Fasting plasma glucose and HbA1c decreased modestly (p < 0.05) after PIO and did not change after PLC. M/I (insulin-stimulated whole-body glucose disposal), adipose tissue insulin resistance (IR) index, insulin secretion/IR (disposition) index and insulinogenic index improved significantly after PIO, but not after PLC. Circulating MCP-1, IL-6, FRK, hsCRP and PAI-1 levels decreased in PIO- as compared with PLC-treated patients, while TNF-α did not change. TNF-α protein expression and TACE enzymatic activity in muscle were significantly reduced by PIO but not PLC. Adiponectin levels increased significantly after PIO as compared with PLC treatment. Given that the mean TACE enzymatic activity level at baseline in the PIO group was 0.29 ± 0.07 (fluorescence units [FU]), and at end of study decreased to 0.05 vs 0.14 in the PLC group, the power to reject the null hypothesis that the population means of the PIO and PLC groups are equal after 6 months is greater than 0.80. Given that M/I was 2.41 ± 0.35 μmol kg(-1) min(-1) (pmol/l)(-1) at baseline and increased by 0.55 in the PIO and 0.17 in the PLC groups, the power to reject the null hypothesis that the population means of the PIO and PLC groups are equal after 6 months is greater than 0.85. The type I error probability associated with this test of this null hypothesis is 0.05. No serious adverse events occurred in either group.
  
  
  CONCLUSIONS
  Low-dose PIO (15 mg/day) improves glycaemic control, beta cell function and inflammatory state in obese patients with type 2 diabetes.
  
  
  BACKGROUND
  Clinical.Trial.gov NCT01223196.
  
  
  BACKGROUND
  This study was funded by TAKEDA.
authors.affiliation: Division of Diabetes, Department of Medicine, University of Texas Health Science Center at San Antonio, 7703 Floyd Curl Drive, San Antonio, TX 78229, USA.
authors.forename: Devjit
authors.initials: D
authors.lastname: Tripathy
authors.forename: Giuseppe
authors.initials: G
authors.lastname: Daniele
authors.forename: Teresa V
authors.initials: TV
authors.lastname: Fiorentino
authors.forename: Zandra
authors.initials: Z
authors.lastname: Perez-Cadena
authors.forename: Alberto
authors.initials: A
authors.lastname: Chavez-Velasquez
authors.forename: Subhash
authors.initials: S
authors.lastname: Kamath
authors.forename: Paolo
authors.initials: P
authors.lastname: Fanti
authors.forename: Christopher
authors.initials: C
authors.lastname: Jenkinson
authors.forename: Francesco
authors.initials: F
authors.lastname: Andreozzi
authors.forename: Massimo
authors.initials: M
authors.lastname: Federici
authors.forename: Amalia
authors.initials: A
authors.lastname: Gastaldelli
authors.forename: Ralph A
authors.initials: RA
authors.lastname: Defronzo
authors.forename: Franco
authors.initials: F
authors.lastname: Folli
mesh_terms: D051722:ADAM Proteins / Q000378:metabolism*; D000072198:ADAM17 Protein; D052242:Adiponectin / Q000097:blood; D018932:Chemokine CCL2 / Q000097:blood; D054428:Chemokine CX3CL1 / Q000097:blood; D003924:Diabetes Mellitus, Type 2 / Q000097:blood* / Q000188:drug therapy*; D005260:Female; D005947:Glucose / Q000378:metabolism*; D005951:Glucose Tolerance Test; D006801:Humans; D007004:Hypoglycemic Agents / Q000627:therapeutic use*; D015850:Interleukin-6 / Q000097:blood; D008297:Male; D008875:Middle Aged; D018482:Muscle, Skeletal / Q000378:metabolism*; D000077205:Pioglitazone; D017395:Plasminogen Activator Inhibitor 1 / Q000097:blood; D045162:Thiazolidinediones / Q000627:therapeutic use*; D019717:Tissue Inhibitor of Metalloproteinase-3 / Q000378:metabolism*; D014409:Tumor Necrosis Factor-alpha / Q000097:blood
chemical_list: D052242:Adiponectin; D018932:Chemokine CCL2; D054428:Chemokine CX3CL1; D007004:Hypoglycemic Agents; D015850:Interleukin-6; D017395:Plasminogen Activator Inhibitor 1; D045162:Thiazolidinediones; D019717:Tissue Inhibitor of Metalloproteinase-3; D014409:Tumor Necrosis Factor-alpha; D051722:ADAM Proteins; D000072198:ADAM17 Protein; C000606462:ADAM17 protein, human; D005947:Glucose; D000077205:Pioglitazone